Kristof1989

Hi im new to the impreza scene. Ive just brought my first impreza and ots got an over heating problem. Ive changed the the thermostat and coolant. The headgasket has been tested by my local garage and they confirmed that it has a recently new and fully working waterpump. The car runs and drives fine for about 30 miles then its will start overheating and not blowing out any hot air from the vents. The water system has been bleed number of times when it over heats i leave it to cool down and the water never seems to go down. Any suggestions. Is there anyone in the worthing west sussex area that could have a look. Thanks

bruce1986

iTrader: (2)

are your fans kicking in?

Kristof1989

I only have one fan, and yer it kicks in... When it over heats the bottom hose is cold and the bottom of the rad near the hose... The rads been flused and water flows freely through it

Baz82

You have an air lock in the cooling system , get someone who is familiar with Subaru's to do a coolant change

Rally fan 555

iTrader: (7)

Sounds like an airlock...

Kristof1989

Its been done a few times now thats the thing. Whats the best way to bleed it and i find out how it was done when i had it done.

Baz82

If its not been done properly each time it will airlock each time .

After experiencing many airlocks in my own impreza and a legacy i had previously,This is the way I do it , other may do it differently but I find this works for me every time.

-Get the front of the car as high as possible on axle stands

-Get a small Funnel that will fit into the turbo coolant hose coming from the header tank (largest hose coming off the header tank going to the turbo).Fill the system through this hose while having the cap off the header tank.

-Once filled (will take about 7 litres roughly) reconnect the hose to the header tank,Leave the cap off the tank, start the engine and turn the temperature control on the dash to fully hot and fan speed to full.

- Get someone to hold the rpm at about 2000rpm , until the temp starts to come up about 1/4 of the dash gauge.Keep topping up the header tank as the level will drop.This will take a bit of time as the heating is on full blast it will take heat away from the engine.

- As the gauge starts to read half-ish,Turn the heating fan speed to half and raise the rpm to 3000rpm, while continuously checking the level in the header tank.Top up as necessary.

-Once the thermostat opens and the bottom rad hose starts to heat up , put the cap on the header tank, check that you have heat in the car (you should at this point) once you are happy with that,turn the heating off and drop the revs.

-Let the car idle for about 5 mins, checking for leaks and check the level of the expansion bottle it should be at the full mark if not add some coolant until it is. Once the rad hoses are pressuized the job is done.

-Take the car off the axle stands

As I said others may do it differently including Subaru specialists, but I find this works everytime.

Hope this gets you sorted

Barry

Kristof1989

Done exactly what you have said and lasted about 100 miles then over heated again :-( i want to over come this problem and not let it get the better of me.

Its had new rad
New thermosat
New water pipes (samco hoses)
Flushed and bleed several times
New water pump

Yet it still overheats after high revs during driving, it always seems to go cold down in the bottom hose area and no hot air comes out the blowers. Yet there is no real water loss. When driving it sometimes feels like it purges and kind of hunts slowly....i.e pulls hold backs pulls holds back if i keep the throttle at one position. Ive had the head gasket chemicly checked but only at low revs, when i rev the car with the cap off the header tank there becomes a very fine foam and bubbles appear. Could the head gasket be leaking and pushing air into the coolant system at high revs?

Any help is muchly appriciated! Thanks guys

jayallen

iTrader: (31)

Yes could well be....

RICHARD J

iTrader: (4)

Sorry to say it but it really sounds like H G failure. Try a new pressure cap on the header tank first you may be lucky.

Kristof1989

Time to bite the bullet and change it early then. Any idea on rough cost? Ive tried a few different caps and still same story

RICHARD J

iTrader: (4)

Try the pressure cap first they cost about a tenner or £40 for a gen STI one. A specialist will charge about £1400 to do the gaskets & probably be about half that to do it yourself.
Good Luck, Iv been there a few times & know how you feel.

The Zohan

When refilling/bleeding the system makes sure the heater is set to hot. I know you say the rad has been flushed and water flows feely but it could still have some of the cores blocked and not be doing its job properly. I would definitely get the cap changed as a matter of urgency.

Kristof1989

Ive changed the cap and still the same story, there is bubble in the header tank when i rev it to about 2000rpm and then creates a foam. Every time ive bleed it the heaters have been on full and set to hot then set to half fan but still on full hot once i feel heat then turned off completly after the rad fan has kicked in and off. When i turn the fans on during driving i do get a strong smell of petrol + money thrown in my face haha :-) got to keep a happy head :-)

stedee

iTrader: (4)

700 quid to diy eek.

seriously if you diy should cost anywhere between £100 and £400 depending on which gaskets you buy. heads may need skimming but check for flatness first dont skim if you dont need to.

btw smell of petrol aint good, check for petrol leaks

The Zohan

Get another sniff test done, DIY (buy the kit from a motor factors) or get a garage to do it to confirm one way or another h/g failure

Kristof1989

I get it done tomoro. Is bubbles normal then? Just rather sort problem asap as i dont drive it much atm as dont want further damage, its only got hot 2-3 times If head gasket has gone will the heads need skimming? Its never gone past the "h"

The Zohan

Bubbles could be several things although if they persist it suggest something is getting into the coolant under pressure (higher pressure than the cooling system when pressurised) - exhaust gases?!? it could be a airlock clearing as well.

sniff test is the way to go. If you have a local radiator specialist then take it to them to get it done.

RICHARD J

iTrader: (4)

Depends how you do it. Quality gaskets, timing belt kit if it's not had one in a while engineering costs fluids and so on & on top of all this it may need a set of shells. To do it properly 700 is not OTT. I'm sure you could Bodge it up on the cheap, but how long will it last? Iv known people DIY it & not fix it atall & end up paying someone else to do it.

Kristof1989

I will get a sniff test done tomoro and see what that shows up.